This invention relates to waveguide apparatus and methods for guiding transmit and receive signals at an earth station of a satellite communication system. This invention relates particularly to a waveguide apparatus for guiding two pairs of orthogonally polarized transmit and receive signals.
Antennas for earth stations of satellite communication systems may be used to receive a signal from a satellite and may also be used to transmit a signal to a satellite by associating appropriate receiver and transmitter units with a feed horn of the antenna.
The capacity of the earth station can also be increased by simultaneously transmitting and receiving two pairs of signals on the same transmit and the same receive frequencies if the two pairs of transmit and receive signals are polarized, because the two pairs of frequencies can be separated according to the sense of polarization of each pair.
The dual polarization, dual frequency operation thus provides the communications user with the opportunity to obtain dual-path operation with only one antenna. The dual-path operation can be used to double the capacity and can be relied on as dual-path redundancy to permit continued operation of at least one path in the event there is a failure of a component in the other path.
The prior art waveguide apparatus and methods that have been used to obtain polarization separation and frequency separation at earth stations have often involved rather large and relatively complex and costly apparatus.